[WorkflowTesting] Use CustomDump to better visualize failure messages

Package.swift

@@ -87,6 +87,7 @@ let package = Package(
         .package(url: "https://github.com/ReactiveCocoa/ReactiveSwift.git", from: "7.1.1"),
         .package(url: "https://github.com/ReactiveX/RxSwift.git", from: "6.2.0"),
         .package(url: "https://github.com/nicklockwood/SwiftFormat", exact: "0.44.14"),
+        .package(url: "https://github.com/pointfreeco/swift-custom-dump.git", from: "0.6.1"),
     ],
     targets: [
         // MARK: Workflow
@@ -103,7 +104,10 @@ let package = Package(
         ),
         .target(
             name: "WorkflowTesting",
-            dependencies: ["Workflow"],
+            dependencies: [
+                .product(name: "CustomDump", package: "swift-custom-dump"),
+                "Workflow",
+            ],
             path: "WorkflowTesting/Sources"
         ),
         .testTarget(

WorkflowTesting.podspec

@@ -19,6 +19,7 @@ Pod::Spec.new do |s|
     s.source_files = 'WorkflowTesting/Sources/**/*.swift'
 
     s.dependency 'Workflow', "#{s.version}"
+    s.dependency 'CustomDump', '~> 0.6.1'
     s.framework = 'XCTest'
 
     s.pod_target_xcconfig = {

WorkflowTesting/Sources/RenderTesterResult.swift

@@ -14,6 +14,7 @@
  * limitations under the License.
  */
 
+import CustomDump
 import Workflow
 import XCTest
 
@@ -77,7 +78,7 @@ public struct RenderTesterResult<WorkflowType: Workflow> {
         line: UInt = #line
     ) -> RenderTesterResult<WorkflowType> where ActionType.WorkflowType == WorkflowType, ActionType: Equatable {
         return verifyAction(file: file, line: line) { appliedAction in
-            XCTAssertEqual(appliedAction, action, file: file, line: line)
+            XCTAssertNoDifference(appliedAction, action, file: file, line: line)
         }
     }
 
@@ -117,7 +118,7 @@ extension RenderTesterResult where WorkflowType.State: Equatable {
         file: StaticString = #file,
         line: UInt = #line
     ) -> RenderTesterResult<WorkflowType> {
-        XCTAssertEqual(state, expectedState, file: file, line: line)
+        XCTAssertNoDifference(state, expectedState, file: file, line: line)
         return self
     }
 }
@@ -131,7 +132,7 @@ extension RenderTesterResult where WorkflowType.Output: Equatable {
         line: UInt = #line
     ) -> RenderTesterResult<WorkflowType> {
         return verifyOutput(file: file, line: line) { output in
-            XCTAssertEqual(output, expectedOutput, file: file, line: line)
+            XCTAssertNoDifference(output, expectedOutput, file: file, line: line)
         }
     }
 }

WorkflowTesting/Sources/WorkflowActionTester.swift

@@ -14,6 +14,7 @@
  * limitations under the License.
  */
 
+import CustomDump
 import Workflow
 import XCTest
 
@@ -32,10 +33,10 @@ extension WorkflowAction {
 ///     .tester(withState: .firstState)
 ///     .send(action: .exampleAction)
 ///     .verifyOutput { output in
-///         XCTAssertEqual(.finished, output)
+///         XCTAssertNoDifference(.finished, output)
 ///     }
 ///     .verifyState { state in
-///         XCTAssertEqual(.differentState, state)
+///         XCTAssertNoDifference(.differentState, state)
 ///     }
 /// ```
 ///
@@ -47,7 +48,7 @@ extension WorkflowAction {
 ///     .send(action: .actionProducingNoOutput)
 ///     .assertNoOutput()
 ///     .verifyState { state in
-///         XCTAssertEqual(.differentState, state)
+///         XCTAssertNoDifference(.differentState, state)
 ///     }
 /// ```
 ///
@@ -143,7 +144,7 @@ extension WorkflowActionTester where WorkflowType.State: Equatable {
     @discardableResult
     public func assert(state expectedState: WorkflowType.State, file: StaticString = #file, line: UInt = #line) -> WorkflowActionTester<WorkflowType, Action> {
         return verifyState { actualState in
-            XCTAssertEqual(actualState, expectedState, file: file, line: line)
+            XCTAssertNoDifference(actualState, expectedState, file: file, line: line)
         }
     }
 }
@@ -157,7 +158,7 @@ extension WorkflowActionTester where WorkflowType.Output: Equatable {
     @discardableResult
     public func assert(output expectedOutput: WorkflowType.Output, file: StaticString = #file, line: UInt = #line) -> WorkflowActionTester<WorkflowType, Action> {
         return verifyOutput { actualOutput in
-            XCTAssertEqual(actualOutput, expectedOutput, file: file, line: line)
+            XCTAssertNoDifference(actualOutput, expectedOutput, file: file, line: line)
         }
     }
 }

WorkflowTesting/Sources/WorkflowRenderTester.swift

@@ -19,6 +19,7 @@
 // `@testable import Workflow` will fail compilation in Release mode.
 #if DEBUG
 
+import CustomDump
 import XCTest
 @testable import Workflow
 
@@ -60,7 +61,7 @@ extension Workflow {
 ///         producingOutput: nil
 ///     )
 ///     .render { rendering in
-///         XCTAssertEqual("expected text on rendering", rendering.text)
+///         XCTAssertNoDifference("expected text on rendering", rendering.text)
 ///     }
 ///     .assert(state: TestWorkflow.State())
 ///     .assert(output: TestWorkflow.Output.finished)
@@ -71,7 +72,7 @@ extension Workflow {
 /// workflow
 ///     .renderTester()
 ///     .render { rendering in
-///         XCTAssertEqual("expected text on rendering", rendering.text)
+///         XCTAssertNoDifference("expected text on rendering", rendering.text)
 ///     }
 /// ```
 ///
@@ -80,7 +81,7 @@ extension Workflow {
 /// workflow
 ///     .renderTester()
 ///     .render { rendering in
-///         XCTAssertEqual("expected text on rendering", rendering.text)
+///         XCTAssertNoDifference("expected text on rendering", rendering.text)
 ///         rendering.updateText("updated")
 ///     }
 ///     .assert(

WorkflowTesting/Tests/WorkflowRenderTesterFailureTests.swift

@@ -227,7 +227,16 @@ final class WorkflowRenderTesterFailureTests: XCTestCase {
                 rendering.doNoopAction(10)
             }
 
-        expectingFailure(#"("noop(10)") is not equal to ("noop(70)")"#) {
+        expectingFailure(
+            """
+            XCTAssertNoDifference failed: …
+
+              − TestAction.noop(10)
+              + TestAction.noop(70)
+
+            (First: −, Second: +)
+            """
+        ) {
             result.assert(action: TestAction.noop(70))
         }
 
@@ -272,7 +281,16 @@ final class WorkflowRenderTesterFailureTests: XCTestCase {
             }
         }
 
-        expectingFailure(#"("sendOutput("second")") is not equal to ("noop(0)")"#) {
+        expectingFailure(
+            """
+            XCTAssertNoDifference failed: …
+
+              − TestAction.sendOutput("second")
+              + TestAction.noop(0)
+
+            (First: −, Second: +)
+            """
+        ) {
             result.assert(action: TestAction.noop(0))
         }
 
@@ -296,7 +314,16 @@ final class WorkflowRenderTesterFailureTests: XCTestCase {
                 rendering.doOutput("hello")
             }
 
-        expectingFailure(#"("string("hello")") is not equal to ("string("nope")")"#) {
+        expectingFailure(
+            """
+            XCTAssertNoDifference failed: …
+
+              − TestWorkflow.Output.string("hello")
+              + TestWorkflow.Output.string("nope")
+
+            (First: −, Second: +)
+            """
+        ) {
             result.assert(output: .string("nope"))
         }